Applied Systems Engineering ASE2000 User Manual page 189

Interrogation flag is unique to IEC protocol and applies when operating in RTU Simulation
and Exchange modes. When enabled for a Monitor-Direction Process-Information ASDU (IEC
terminology for input points), it causes that ASDU to be queued for transmission after receipt of an
Interrogation request. Integrated Total ASDUs are queued in response to Counter Interrogation
requests. Other applicable ASDUs are queued in response to General Interrogation requests.
There is no special processing for Group Interrogations.
Data Link Layer Function (IEC 60870-5-101 only) is used to select the Data Link function code
for transmission. Except for one case, this field is informational and should not be altered. The
one case where it can be changed is to switch between User Data (No Confirm) and User Data
(Confirm). If the default function code is either of these, it can be safely modified to the other.
The setting (Confirm or Not) is not used for processing incoming messages.
Data Link Layer PRM and FCV checkboxes define whether or not the PRM and FCV bits
should be set in the function code byte. The ASE2000 always sets there fields correctly based
on the Data Link function code. If modified, an incorrectly formatted message will be sent. The
checkboxes are included in this menu only for that purpose, that is, to transmit an incorrectly
formatted message to verify error handling by another IEC device.
DL Addr (IEC 60870-5-101 only) defines the exchange's data link address. Either an '*' or specific
value can be entered. An '*' instructs the ASE2000 to use the system default (see Properties Tab
and Protocol).
If the system default is also '*', then, on reception, any address is considered valid. On transmission
in Master Simulation mode, 0 is used. On transmission in RTU Simulation mode, the data link
address extracted from the corresponding request message is used.
If the value is not '*', then the entered value is used for both transmission and reception. In this
case, a message received with any other address is considered invalid.
Comm Addr defines the exchange's common address of ASDU. Either an '*' or specific value
can be entered. An '*' instructs the ASE2000 to use the system default (see Properties Tab and
Protocol).
If the system default is also '*', then, on reception, any address is considered valid. On transmission
in Master or RTU Simulation mode, 0 is used.
If the value is not '*', then the entered value is used for both transmission and reception. In this
case, a message received with any other address is considered invalid.
ASDU Type ID defines the exchange's application data type, such as Single Point or Measured
Value. While this field can be changed from the associated pull-down list, there should be no
reason to do so since the ASE2000 provides one exchange for every ASDU Type. The Type
and the exchange name should coincide as it would be confusing to change one without also
changing the other.
Cause Of Transmission, in general, should not be modified except for Process Information
ASDUs in the Monitor Direction, and then only when operating in Exchange and RTU Simulation
modes. For these Exchanges, the Cause Of Transmission defines the value used in all messages
sent except Interrogation responses (in which case, the cause is changed to "Interrogated"). The
ASE2000 assigns one of the many acceptable settings when the exchange is created.
ASE2000 V2 Communication Test Set User Manual 189